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Happy Hour

Ah, innovation! What would we do without this driver of new technology and new consumer markets? Science is the breeding ground for said technological creativity, and even those scientists who focus primarily on curiosity-driven basic research -- such as theoretical physics -- often find their curiosity piqued by the challenge of finding a solution to a real-world problem.

Take, for example, Albert Einstein, best known to the general public for devising the world’s most famous equation: E=mc2. But his contributions to physics extend over an impressively broad range of topics, including Brownian motion, the photoelectric effect, special and general relativity, and stimulated emission, which led to the development of the laser. Less well known, even among physicists, is his work with Leo Szilard to develop an energy efficient absorption refrigerator with no moving parts.

Szilard was born in Budapest, Hungary in 1848, the son of a civil engineer. In 1916, he enrolled as an engineering student at Budapest Technical University, but his education was interrupted the following year, when he joined the Austro-Hungarian Army. After the war, he attended the Institute of Technology in Berlin -- not so much by choice, as because of "racial quotas" (he fled Berlin in 1933 to escape Nazi persecution) -- where he met Albert Einstein and Max Planck. Szilard earned his doctorate in physics in 1922, and he and Einstein became close friends.

His dissertation was in thermodynamics, and in 1929 he published a seminal paper, “On the Lessening of Entropy in a Thermodynamic System by Interference of an Intelligent Being” – part of an ongoing attempt by physicists to better understand the “Maxwell’s Demon” thought experiment first proposed by James Clerk Maxwell. It contained a description of “Szilard’s engine,” a hypothetical heat engine that violates the second law of thermodynamics by continuously turning the heat energy of its environment into work.

This was the example the Spousal Unit featured in a blog post just before the Thanksgiving holiday, about a new Maxwell’s-Demon-type experiment conducted by Shoichi Toyabe and collaborators in Japan, that appeared recently in Nature. Alas, as with many things in the nuanced field of thermodynamics, the result was misinterpreted in several press accounts as converting information into energy. Per the Spousal Unit: "That’s not quite right — it’s more like using information to extract energy from a heat bath." And he cited Szilard's Engine to illustrate the difference:

Consider two pistons with the same number of gas particles inside, with the same total energy. But the top container is in a low-entropy state with all the gas on one side of the piston; the bottom container is in a high-entropy state with the gas equally spread out.You see the difference — from the top configuration we can extract useful work by simply allowing the piston to expand. In the process, the total energy of the gas goes down (it cools off). But in the bottom piston, nothing’s going to happen. There’s just as much energy inside there, but we can’t get it out because it’s in a high-entropy state.

In 1929, Leó Szilárd used a similar setup to establish an amazing result: the connection between energy and information. The connection is not that “information carries energy”; if I tell you some information about gas particles in a box, that doesn’t change their total energy. But it does help you extract that energy. Effectively, learning more information lowers the entropy of the gas. That’s a loosey-goosey statement, [we love that the Spousal Unit says stuff like "loosey-goosey"] because there is more than one way to define “entropy”; but one reasonable definition is that the entropy is a measure of the information you don’t have about a system. (In the piston above, we know more about the gas in the low-entropy setup, since we have a better idea of where it is localized.)

Anyway, the point is, that early dissertation work of Leo's proved useful when it came time to design a new kind of refrigerator. Szilard had a knack for invention, applying for patents for an x-ray sensitive cell and improvements to mercury vapor lamps while still a young scientist. He also filed patents for an electron microscope, as well as the linear accelerator and the cyclotron, all of which have helped revolutionize physics research. Szilard’s most important contribution to 20th century physics was the neutron chain reaction, first conceived in 1933. In 1955, he and Enrico Fermi received a joint patent on the first nuclear reactor, which the US Patent Office compared in significant to the patents issued for the telegraph and telephone in the 19th century.

Einstein wasn’t a stranger to the patent process, either, having worked as a patent clerk in Berlin as a young man. He later received a patent with a German engineer named Rudolf Goldschmidt in 1934 for a working prototype of a hearing aid. A singer of Einstein’s acquaintance who suffered hearing loss provided the inspiration for the invention.

The impetus for the two men’s collaboration on a refrigerator occurred in 1926, when newspapers reported the tragic death of an entire family in Berlin, due to toxic gas fumes that leaked throughout the house while they slept, the result of a broken refrigerator seal. Such leaks were occurring with alarming frequency as more people replaced traditional ice boxes with modern mechanical refrigerators which relied on poisonous gases like methyl chloride, ammonia and sulfur dioxide as refrigerants. Einstein was deeply affected by the tragedy, and told Szilard that there must be a better design than the mechanical compressors and toxic gases used in the modern refrigerator. Together they set out to find one.

And now, a brief primer on how your refrigerator works. One of the neat things about thermodynamics is that if you can create a large enough differential -- for example, a big difference in temperature between two compartments -- you've got yourself a handy energy source to tap into should the need arise. Refrigerators work on a simple concept known as the Carnot cycle. Gas -- usually ammonia or freon these days, not the toxic gases more common during Einstein's era -- is pressurized in a chamber, said pressure causes that gas to heat up, this heat is then dissipated by coils on the back of the appliance, and the gas condenses into a liquid. It's still highly pressurized, sufficiently so that the liquid flows through a hole to a second low-pressure chamber.

That abrupt change in pressure makes the liquid ammonia boil and vaporize into a gas again, also dropping its temperature -- thereby keeping your perishable foodstuffs nicely chilled. The cold gas gets sucked back into the first chamber, and the entire cycle repeats ad infinitum -- or at least as long as the appliance is plugged in. That's always the catch, you see. The refrigerator is not a truly "closed system": it gets a constant influx of energy from the wall outlet that enables it to operate continuously. Left on its own, without that crucial influx, and the interior would cease to be nicely chilled, and all the food therein would perish.

To address the toxic gas concerns, Einstein and Szilard focused their attention on absorption refrigerators, in which a heat source – in that time, a natural gas flame – is used to drive the absorption process and release coolant from a chemical solution, instead of a mechanical compressor. An earlier version of this technology had been introduced in 1922 by Swiss inventors, and Szilard found a way to improve on their design, drawing on his expertise in thermodynamics. His heat source drove a combination of gases and liquids through three interconnected circuits.

They still needed some version of a Carnot cycle. Anyone who lives at high altitudes (Denver residents, we're looking at you!) knows that water boils at lower temperatures when the air pressure is lower, as is the case in the Mile-High City. (Air pressures are higher at sea level.) The Einstein-Szilard fridge exploited this effect, using just pressurized ammonia, butane and water, with no need for electricity to operate the appliance (depending on your choice of heat source), and no moving parts -- thereby eliminating the possibility of seal failure.

One side contained a flask filled with butane (the evaporator), which was then injected by a new vapor (the ammonia) just above the butane, creating that all-important differential. This would decrease the boiling temperature, and as the liquid water boiled off, it sapped energy from its surroundings -- chilling the compartment in the process.

One of the components the two physicists designed for their refrigerator was the Einstein-Szilard electromagnetic pump, which had no moving parts, relying instead on generating an electromagnetic field by running alternating current through coils. The field moved a liquid metal, and the metal, in turn, served as a piston and compressed a refrigerant. The rest of the process worked much like today’s conventional refrigerators.

Einstein and Szilard needed an engineer to help them design a working prototype, and they found one in Albert Korodi, who first met Szilard when both were engineering students at the Budapest Technical University, and were neighbors and good friends when both later moved to Berlin.

The German company A.E.G. agreed to develop the pump technology, and hired Korodi as a full-time engineer. But the device was noisy due to cavitation as the liquid metal passed through the pump. One contemporary researcher said it “howled like a jackal,” although Korodi claimed it sounded more like rushing water. Korodi reduced the noise significantly by varying the voltage and increasing the number of coils in the pump. Another challenge was the choice of liquid metal. Mercury wasn’t sufficiently conductive, so the pump used a potassium-sodium alloy instead, which required a special sealed system because it is so chemically reactive.

Despite filing more than 45 patent applications in six different countries, none of Einstein and Szilard’s alternative designs for refrigerators ever became a consumer product, although several were licensed, thereby providing a tidy bit of extra income for the scientists over the years. And the Einstein/Szilard pump proved useful for cooling breeder reactors. The prototypes were not energy efficient, and the Great Depression hit many potential manufacturers hard. But it was the introduction of a new non-toxic refrigerant, freon, in 1930 that spelled doom for the Einstein/Szilard refrigerator. The economics supported the freon-based mechanical compressor technology, and that's what most folks still use today.

Interest in their designs has revived in recent years, fueled by environmental concerns over climate change and the impact of freon and other chlorofluorocarbons on the ozone layer, as well as the need to find alternative energy sources. In 2008, a team at Oxford University led by Malcolm McCulloch (an electrical engineer who is passionate about green technologies) built a prototype as part of a project to develop more robust appliances. They modified the design slightly, replacing the types of gases used, in hopes of quadrupling the efficiency of Einstein and Szilard's original design. McCulloch is also toying with the notion of using a solar-powered heat pump to make the appliance even more energy efficient.

Meanwhile, other scientists at rival Cambridge University have explored cooling via magnetic fields, with no need for adding extra energy, in yet another modified design of the Einstein-Szilard fridge. "Ours works in a similar way (to freon fridges) but instead of using a gas we use a magnetic field and a special metal alloy," project manager Neil Wilson told Green Optimistic in 2008. "When the magnetic field is next to the alloy, it's like compressing the gas, and when the magnetic field leaves, it's like expanding the gas. This effect can be seen in rubber bands -- when you stretch the band it gets hot and when you let the band contract it gets cold."

And finally, a former graduate student at Georgia Tech, Andy Delano, also built a prototype of one of Einstein and Szilard’s designs as part of his master's and doctoral thesis work. "Literally, you heat one end and the other gets cold," Delano explained at the time. He researched the refrigeration cycle and modeled it on a computer, using his own money to build the prototype. His then-roommate just happened to be majoring in civil engineering, and helped weld the prototype together, while his brother (another Georgia Tech alum) drew on his industrial design degree to create an animated version of Einstein and Szilard's original patent diagram, bringing the movement of the various fluids to life. Delano's version used electric resistance heaters as the heat source, mostly for convenience, but a small gas burner or solar energy sources could also be used.

It took months for Delano and his partners to finish building the prototype, but good news -- it worked right off the bat. Well, almost: at first, he got ice, so he tweaked the mix of chemicals to get a chill, not not an outright freeze. It does bode well for the possibility of creating a refrigerator/freezer combination in the future -- although that future is probably still pretty far off. Still, all these prototypes are further proof of principle that Einstein and Szilard were clearly onto something -- they were just 70-odd years too soon.

Still zero time to blog, and my co-bloggers are equally silent, so here's another blast from the past, about an awesome potential application for free electron lasers: replacing liposuction as the procedure of choice for discriminating folks desiring to rid themselves of excess baggage. Literally.

In a perfect world, bad things wouldn't happen to good people. There would be no pain, no suffering, no sickness -- and no calories. Those obnoxious little units, first introduced in the nutritional, food-related sense in the 1890s, have caused more grief for the human waistline over the ages than, say, girdles or whalebone corsets (although the latter were known to sometimes damage internal organs). Most women and -- let's be honest, now -- many men waste a fairly considerable amount of time worrying about unwanted stores of fat globules. It's no coincidence that one of the most popular features of Judgment City -- a sort of waiting room for the afterlife in the 1991 Albert Brooks film Defending Your Life -- is the fact that during your stay there, you can eat whatever you like without gaining an ounce. (That's where Jen-Luc Piquant is going for her next vacation: hello, Judgment City!)

I'm happy to report that there may be new hope for expanding waistlines and flabby thighs. Scientists at the Thomas Jefferson National Accelerator Facility (known affectionately as "JLab") have demonstrated that a laser can heat (read, "burn away") fat in the body without scorching the over-lying skin. This in turn could lead to revolutionary new laser therapies to treat such chronic bugbears as severe acne, artery plaque, and -- you guessed it -- unwanted cellulite. These very exciting results were presented this morning in Boston at the 26th annual meeting of the American Society for Laser Medicine and Surgery (ASLMS). I was not actually there, alas, to witness this historic announcement in person, but I was among the many proud recipients of the JLab press release last Thursday, and have only been prevented from sharing the news with you all until now because of a compulsory media embargo. (We try to always respect the embargo here at Cocktail Party Physics. It'd just be rude to do otherwise.)

First, a few words about lasers. The question of who actually invented this useful little device is a thorny one, and the subject of many nasty lawsuits over several decades, but most would agree that the underlying fundamental physics comes to us courtesy of good ol' Albert Einstein. It was just a little idea he was developing on the side for a lark to take a break from the rigors of general relativity -- a side project that ended up spawning a multi-billion-dollar industry. In 1917 he published a paper that broached the possibility of something called "stimulated emission." (Yes, I know: it's an unfortunate choice of words. But that's what it's called, so try to keep the snickering to a minimum, 'kay?)

At the heart of a laser is a "lasing medium" -- usually a crystal of some sort, like ruby -- and if you pump the atoms in that material (oh, stop it!) with intense flashes of light or electricity, it will eventually emit the excess energy as photons. I won't go into all the complicated details here; you can find more details here and here. But the end result is a tightly focused beam of light in which all the photons are traveling in the same direction, rather than diffusing outward all willy-nilly, in every direction at once. So "laser" is short for "Light Amplification by Stimulated Emission of Radiation." (We're offering a brand new physics cocktail, called the Laser Beam, in its honor. See sidebar.)

The problem with conventional lasers is that by their very nature, they only emit light at one given frequency, which is determined by whatever material one is using as the lasing medium. JLab pioneered free electron lasers (FELs), which emit intense, powerful beams of laser light that can be tuned to whatever wavelength (color) of the electromagnetic spectrum one needs for the purpose at hand. This makes an FEL incredibly flexible and therefore useful for a broad range of applications, including processing plastics, synthetic fibers, electronics components, and all kinds of cutting-edge materials with unique properties. And it can do so far more cheaply than more traditional manufacturing tools. That tunability also means the instrument can be tailored to three infrared wavelengths where -- the researchers found -- fat heats up more efficiently than water, making it possible to selectively heat fat tissue with infrared laser light. They tested this capability first on actual human fat (obtained from "surgically discarded normal tissue"), and then on skin-and-fat tissue samples taken from pigs.

Jen-Luc Piquant, for one, is delighted that the good folks at JLab finally got around to addressing the dire need for new ways to get thinner thighs in 30 days -- preferably ones that don't involve any actual effort. It's about time we brought out the big guns. Just look at the size of that thing! And that's only one of the system's many components... This country may or may not be facing an "obesity epidemic," depending
on which conflicting study one chooses to believe, but a quick look
around the average suburban mall would offer quite a bit of anecdotal
evidence in favor of the "pro"-epidemic view. Of course, excess flab isn't a new problem for the human race. Far from it. Among other notable historical figures, the English poet Lord Byron struggled mightily with his weight, despite being the quintessential ladies' man (club foot and all), and routinely went on "slimming" regimens like liquid diets.

So fad diets predate Dr. Atkins. In the early 20th century, Horace Fletcher -- a.k.a. "the chew-chew man" -- advocated controlling food consumption by chewing one's food until it was liquid. Shortly before he died in 1919, Dr. Lulu Hunt Peters published the first bestselling diet book, Diet and Health, which was also the first to promote the idea of counting calories to control weight -- then quite a new concept. It had only been 20 years or so since the chemists Wilbur Atwater and Russell Chittenden came up with the notion of measuring food as units of heat that could be produced by burning it. That's all a "calorie" really is: the amount of heat energy produced when the food is burned to ashes, under controlled laboratory conditions. It's not something that's actually "in" food.

The success of Peters' book spawned an entire industry. Think the Atkins and South Beach Diets were innovative and original? Think again. The emphasis on "food combinations" dates back to the 1920s and 1930s. William H. Hay, for example, believed proteins, starches and fruits should be eaten separately to avoid "acidosis." It's unclear to me what this is, but apparently it "drained vitality and led to fat." (Jen-Luc reminds me -- somewhat unkindly, I think -- that I have had boyfriends who could be considered the human embodiment of acidosis.) He also recommended a daily enema to "flush out the poisons" -- an approach that can still be seen today in the popularity (in certain elite circles) of "colonics."

With his book, Look Younger, Live Longer, Gaylord Hauser drew the admiration of the likes of Greta Garbo and Paulette Goddard with his emphasis on Vitamin-B rich foods like brewers yeast, yogurt, wheat germ and blackstrap molasses. He was also one of the first to develop his own line of special foods and supplements in accordance with that diet plan. Then there was the so-called "magic pairs" diet, extolling the supposedly increased fat-burning properties of certain food combinations, like (we kid you not) lamb chops and pineapple. Plus ca change.... We're still looking for that "magic bullet." When it comes to fad diets, there is truly nothing new under the sun. And they aren't any more or less effective than they were back then.

We bandy about the word quite promiscuously, but a "calorie" is not as tangible as one might think. In the realm of science (specifically, thermodynamics), calories apply to anything that contains energy, such as a
gallon of gasoline. The calories in food are technically
"kilocalories," according to how the units are strictly defined in
science. For scientists, a calorie is simply the amount of energy
(heat) required to raise the temperature of one gram of water by 1
degree Celsius (1.8 degrees Fahrenheit), and 1000 calories is
equivalent to 1 kilocalorie. So that Power Bar I just consumed for breakfast contained 270 food calories, which translates into 270,000 regular calories. And that four miles I'll be running this afternoon should burn 400 "food calories"; it sounds like a much more impressive amount when transposed into 400,000 regular calories.

For weight management purposes, it's sufficient just to burn up the calories. But all that energy released when calories are burned can also be harnessed to do
some kind of useful task. For instance, prisoners in
19th century New York prisons were forced to walk on treadmills as
punishment, and that energy was used to grind grain for the inmates'
daily bread. I found an interesting comparison chart
at How Stuff Works. It turns out that the calories contained in five
pounds of spaghetti would yield enough energy to brew a pot of coffee,
while those in a single slice of cherry cheesecake would operate a
light bulb for an hour and a half. And if you need to drive 88 miles to
visit friends or relatives, you'd need to burn the calories contained
in 217 Big Macs. (Talk about carb-loading. Better start chowing down the night before.)

Back in February, I stumbled upon a fascinating short article in Wired
about creative ways to harness the energy from gym exercise to perform useful functions. An artist named
Laurie Palmer began musing about all the wasted energy being produced
in gyms all across the country, by Americans on stationary bikes,
elliptical machines, or treadmills. So she set up the online "Notions
of Expenditure" project a year ago, in which people can contribute their
ideas for turning exercisers into generators of energy. Unfortunately, unless you're Lance Armstrong, it's not a lot of energy: most people on a stationary bike
only produce between 75 and 150 watts.

It all seems like a great deal of work, for very little payoff, doesn't it? Hence the appeal of the JLab approach: no muss, no fuss, no obsessively writing down every morsel that passes one's lips in a little "food diary." No special meals or supplements, elaborately orchestrated food combinations, or those telltale minute surgical scars from conventional liposuction -- just one really big free electron laser facility that hunts down fat and zaps it away without damaging one's outer layer of skin. Needless to say, Jen-Luc Piquant is ecstatic at the prospect, and is preparing to indulge in large bowls of her favorite virtual penang curry over coconut sticky rice, among other rich and calorie-laden delicacies. It's almost as it JLab's FEL has turned our world into one giant Judgment City where we can eat whatever we want with no dietary consequences. "Go ahead," she exhorts, a bit irresponsibly. "Indulge in that over sized blueberry scone. Why bother watching what you eat when you can just zap that fat away whenever you feel like it?"

As usual, Jen-Luc is letting her enthusiasm over-ride her common sense. Operating an FEL isn't cheap, nor is scheduling time at the facility as easy as scheduling a doctor's appointment -- or a visit to one's local Liposuctor. And let's not forget that for now, at least, it's just proof of principle. Commercial development of any application takes a lot more time. And money. So tempting though it may be to throw dietary caution to the wind, I think I'll stick with my tried and true Thermodynamics Diet: you know, that one where you have to burn more calories than you consume to lose weight. Sure, it lacks the guilt-free ease and panache of those flashier fad diets, and requires far more actual effort. On the other hand, it has withstood the test of time.

NOTE: I have a couple of blog posts in the works, and two others percolating in the back of my brain. But today the galleys for The Calculus Diaries arrived, so I'll be spending the next few evenings combing through those pages making sure embarrassing typos don't show up in the final published book. There's a lot of math and stuff in the appendices, too, so my brain will be pretty fried by the time I'm done. But I'm kind of enjoying the occasional visit to the cocktail party archives, so here's my 2006 take on the many-headed Hydra of perpetual motion scams. Sure, Steorn has come and gone since then -- another one will pop up in its place. This is a post that, I'm sorry to say, will likely always be relevant.

Oh dear god in heaven Great Flying Spaghetti Monster, not again. I came back from a lovely weekend in the Windy City to find yet another misguided idealist named Sean McCarthy -- less kindly folks, like Jen-Luc Piquant, might say "demented crackpot" or "opportunistic con artist" -- announcing that his little start-up company in Ireland, called Steorn, has overthrown the laws of thermodynamics and developed a technique that produces more energy than it consumes -- the equivalent of a perpetual motion machine. According to this news item, the mysterious process "involves magnetic fields configured in precisely the right way. Using the magnets results in a motor that's more than 100% efficient, essentially creating energy."

Our reaction to this potentially earth-shattering news? Not bloody likely. It's an opinion we expect is shared by anyone with the least smattering of comprehension of basic thermodynamical principles and the history of perpetual motion machines. People like Bob Park, the University of Maryland physics professor (and author of Voodoo Science) who has been skewering all manner of pseudoscientific claims for two decades via his electronic newsletter, What's New. (We can't wait for his acidic take on this latest claim in this coming Friday's edition.) This "fake debate" has been running so long that the physics community has moved beyond outrage and frustration to unmitigated boredom with the continued need to debunk free energy claims. In fact, it's taking all the energy we can muster to overcome our own boredom (a.k.a., mental inertia) with the issue to write this post. What the heck -- we'll reiterate the arguments yet one more time. But this is the last time, absolutely the last, cross my heart and hope to die, because death would be preferable to wasting any more time on something that ought to have been settled long ago.

As Park would be happy to tell you, people have been chasing this particular pipe dream for centuries, at least -- possibly even millennia. Biology has its bugbear in the form of Intelligent Design; the physics equivalent is perpetual motion, also known as "free energy" schemes. One of the earliest depictions of such a device can be found in the 12th century writings of Villand Honnecourt, and mentions become more frequent in historical records from then on. For example, a 15th century Italian physicist and alchemist claimed to have invented a self-blowing windmill, while in the 1670s, the Bishop of Chester designed several devices he claimed used perpetual motion.

Free energy proponents are fond of pointing out that in the 16th century, no less a luminary than Leonardo da Vinci sketched quite a few designs for perpetual motion machines based on the waterwheel mechanism,
but they neglect to mention that publicly, Leonardo denounced such schemes: "Oh ye seekers after perpetual motion, how many vain chimeras have you pursued? Go and take your place with the alchemists." (Alchemy wasn't definitively debunked until the end of the 17th century, so as usual, Leonardo was a good century ahead of his time in denouncing alchemists.)

Among the most well-known "inventors" is Robert Fludd, a 16th century English physician and alchemist who claimed, in 1618, to have found a means of producing sufficient energy to operate a waterwheel -- a common technology dating back to the Roman Empire in 20 BC, and still used today in hydroelectric power stations -- to grind flour in a mill, without relying on a powering stream.

Fludd figured he could use the waterwheel to drive a pump, in addition to grinding flour. The water would turn the wheel and then be pumped back up into a standing reservoir and reused. The mill could therefore run indefinitely on this fixed supply of water. But he neglected to figure in the fact that the water would have to be lifted back up the same distance it fell -- working against gravity -- as it also turned the wheel to grind the grain into flour. Merely pumping the water back up into the reservoir would require so much energy that there wouldn't be any left to grind the flour, even considering the supposed "extra" energy generated by the rotating waterwheel.

Despite his love of alchemy, Fludd was nonetheless quite a respectable scientist and we can excuse his misguided enthusiasm for his design, because he just didn't know any better. Okay, Leonardo was smart enough to know better, despite dabbling in perpetual motion devices for his own amusement, but he was an undisputed genius. He was also a bit of a visionary, not inclined to formulate solid theoretical "proofs", either pro or con, for such machines. And he wasn't alone in this oversight. At the time Fludd announced his waterwheel scheme, no one had codified the laws of thermodynamics in precise, physical terms. That process began in the early 19th century, with the work of a little-known French physicist named Sadi Carnot.

Carnot was the son of a French aristocrat --his father was one of the most powerful men in France prior to Napoleon's ignominious defeat. He was fascinated by steam engines, and became obsessed with making them more efficient. (For some reason, he seemed to think England's superior technology in this area had contributed to Napoleon's downfall and the loss of his family's prestige and fortune.) In 1824 he published Reflections on the Motive Power of Fire, which described a theoretical "heat engine" that produced an amount of work equal to the heat energy put into the system.

Technically, this would be a perpetual motion machine of the first kind. (There are actually two different types of perpetual motion machines, each violating one of the two laws of thermodynamics.) But Carnot was no fool: he knew from endless experimentation that in practice, his design would always lose a small amount of energy to things like friction, noise and vibration. His lasting contribution was to set out the physical boundaries so precisely that, after his untimely death from cholera at the age of 32, Rudolf Clausius and William Thomson (Lord Kelvin) would draw on his work to build the foundations of modern thermodynamics in the 1840s and 1850s. Carnot also invented the so-called "Carnot cycle," drawing energy from temperature differences -- the basis of modern-day refrigerators and air-conditioners.

Quick refresher course for our lay readers (scientists and other uber-geeks, feel free to skip this part): The first law of thermodynamics says energy is conserved, which means it can be converted from one form to another, but neither created ex nihilo, nor destroyed -- even if a machine is 100% efficient, which it could never be. That's the essence of the second law, which says that a small amount of energy will always be irretrievably lost when energy is converted -- and it must be converted (and harnessed!) to produce useful work (we use that term here in the precise physics sense).

It's hardly a Big Physics Secret that perpetual motion and free energy machines just... don't... work (in the non-precise layman's sense)! There is massive amounts of information out there, adeptly debunking claims of perpetual motion and demonstrating why such schemes never work. (For a lighter take on this topic, check out the Museum of Unworkable Devices, which has entire pages devoted to demonstrating the infeasibility of perpetual motion machines.) The truth is out there, folks, for anyone who can be bothered to spend 15 minutes looking for it. And yet, unlike alchemy, this pointless quest refuses to die, like horror movie icons Jason of the Friday the 13th series, or Nightmare on Elm Street's Freddy Krueger. Perpetual motion is a weed that keeps popping up despite regular blastings of chemical agents, or a cancer that stubbornly resists all forms of treatment. Feel free to suggest your own favorite metaphor; the possibilities abound.

Some perpetual motion proponents are frauds: their machines have hidden energy sources, like cleverly concealed batteries. The 18th century clockmaker Johan Ernst Elias Bessler designed over 300 perpetual motion machines, and seemed to have succeeded in building a wheel that rotated for 40 days in a locked room. His claim was unverifiable -- Bessler refused to let anyone study his machine closely -- but unlikely; historians suspect he concealed a clockwork mechanism in the large axle of the wheel to keep it running so long. Among the most notorious of modern hucksters is Dennis Lee, who hawks his various "free electricity" schemes in churches and auditoriums across the country, undeterred by the naysayers -- or by the the various state attorney general's offices who have sought legal sanctions against him.

In most cases, however, the culprit isn't fraud, but wishful thinking, combined with just a wee bit of self-delusion and hubris. Would-be inventors simply miscalculate the amount of energy produced and consumed (these can be tricky calculations, after all). Yet they are sincerely convinced that they're onto something, that they have succeeded in achieving a feat that has eluded the best scientific minds for centuries. People like McCarthy refuse to believe that there is no free lunch, despite overwhelming evidence to the contrary. There are enough of these kinds of people that the American Physical Society felt compelled to issue a statement in 2003 "deploring" all attempts to "mislead and defraud the public" via such claims. At the time it was released, the APS Executive Board also publicly commented on the proliferation of free energy schemes and perpetual motion devices, stating unequivocally, "Such devices directly violate the most fundamental laws of nature, laws that have guided the scientific progress that is transforming our world."

This is not to say that scientists are unwilling to question and explore possible violations of the laws of thermodynamics. The physicists are on top of it, people! Truly! Not only have they conducted countless experiments, but they've even proposed ingenious "thought experiments" just to challenge the conventional scientific thinking on the matter. The most notorious of these is "Maxwell's demon, " discussed in an earlier post, but everyone's favorite physics prankster/pundit, Richard Feynman, also got into the act when he proposed a "Brownian ratchet" device during a physics lecture at Caltech on May 11, 1962.

The basic device is depicted in the diagram at right. Essentially, the ratchet mechanism ensures that the attached shaft can only turn in one direction. The idea is that random motions in the gas filling the container will cause atoms to bombard the fins. There will be inevitable statistical fluctuations in this process, so at some point there will be more impacts on one side of the fins than on another, and the shaft will turn slightly -- but only in one direction. Forever. So it could theoretically be used to generate power.

Feynman's thought experiment is most instructive, since the underlying violation of thermodynamics is quite subtle at first glance. You see, every time the ratchet moves, the peg will bounce off the gear teeth, producing heat. As time passes, the gear teeth will become as warm -- if not warmer -- as the gas in the container. So what? You're probably thinking. Well, that extra heat will cause the ratchet peg to bounce upwards regularly, and statistically speaking -- since the shaft's motion is by definition random -- sometimes the shaft will slip backwards instead of turning in the desired direction. In fact, if the wheel gets warmer than the gas, the cog will move in the opposite direction than Feynman originally planned.

Okay, you say, let's just make the spring stronger to prevent this inconvenient bouncing. Nice try, but no cigar. If we do this, the molecular motion won't produce enough force to overcome the stiffer spring and allow the ratchet to turn -- in any direction. Bottom line: as often as the machine ratchets forward, it will slip back, canceling out any extra "energy" it produces, and most likely losing energy in the long run, unless we find some way to replenish that lost energy from an outside source. Ironically, while Feynman's device was purely hypothetical and designed to teach his students the inviolability of the second law, it led to the development of Brownian motors, which do produce useful work, without violating thermodynamics. (You can find technical explanations of how and why here, here and here, and probably about 8 million other places on the World Wide Web.)

As recently as 2002, the University of San Diego sponsored the First International Conference on Quantum Limits to the Second Law, and maintains a Web site devoted to new challenges and accompanying critiques. So this isn't a question of the "Scientific Establishment" simply being close-minded to the possibility. Physics is all about the ongoing quest for knowledge, after all, and if physicists sometimes seem a bit dogmatic about their stance on the second law's inviolability, that's because it's backed up by massive amounts of empirical data amassed over centuries of experimental observation. The odds are definitely in the second law's favor. There has not been a shred of convincing scientific evidence to date demonstrating any exception to it. As Sir Arthur Eddington famously observed in 1948's The Nature of the Physical World:

"The second law of thermodynamics holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations, then so much for the worse for Maxwell's equations. If it is found to be contradicted by observation, well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation."

Eddington's statement is as true today as it was almost 60 years ago; in fact, the US patent office routinely rejects applications for free energy schemes outright, based solely on the second law of thermodynamics. McCarthy and his colleagues at Steorn know all of this. That's why they've placed an ad in The Economist asking for skeptical scientists to sit on a 12-member panel to help validate the company's new process. "If we're right, that will come out in due course. If we're wrong, that will come out. It's such a big claim that it has to be validated by experts," McCarthy told Wired News. It sounds so fair-minded and sensible, right?

Wrong. Frankly, it strikes me as more than a bit disingenuous. The ad quotes playwright George Bernard Shaw, who once observed, "All great truths begin as blasphemies." So anyone who refuses to at least consider the claim risks looking like a close-minded protector of the Scientific Status Quo. McCarthy is deliberately evoking the persecuted specters of Copernicus and Galileo to goad the scientific community into lending credence to his claims. (We offer Carl Sagan's classic retort: "They laughed at Newton. They laughed at Galileo. But they also laughed at Bozo the Clown.") It worked, too: not only have I written this post, but thus far, some 1500 scientists have offered to help test a claim that has about a 0.0000001% chance of being scientifically valid -- and we're being charitable. The odds might not even be that good. Yet the company has already filed numerous patent applications, and has
announced its plans to incorporate the technology into long-lived batteries for cell phones and
laptops. Can you say "overconfident"?

As a writer who frequently must work while traveling, I would love to have a laptop battery that lasts longer than a few hours between rechargings, never mind indefinitely. But I am, at heart, a pragmatic realist and will not succumb to mere wishful thinking in this matter. My money's betting that the "panel of experts" concludes, in record time, that Steorn's engineers are either committing fraud, or have erred in their energy calculations. Repeat after me, people: when it comes to energy, you can't win, and you can't break even. Energy is never "free." Please, we beg of you, make this your mantra. Because we're all getting just a wee bit tired of having to constantly remind everyone of such a fundamental point. Over. And. Over. Again.

I am in Portland for the day, having dragged myself out of bed at an ungodly hour (4 AM) to catch my flight. (On the plus side, there is almost no traffic on LA freeways at that hour.) The reason: to visit the city's Green Microgym founded by personal trainer Adam Boesel last year. Perhaps you read some of the press coverage the opening generated: Boesel has retrofitted much of his exercise equipment (stationary bikes, treadmills, elliptical machines) so that gym members can produce a little bit of usable energy during their workouts -- not a lot, mind you, but enough to run the fans, for example, or the stereo system. Combine that with other strategies for improving energy efficiency, and Boege keeps his electricity costs to a bare minimum. In time, he thinks he can break even, and maybe even turn a small profit.

He's not the first to ponder the potential of all those city dwellers -- ahem! like me! -- spending hours upon hours running or cycling in place to stay fit and trim, like hamsters on one of those little wheels, with little else to show for it other than improved health (which, admittedly, is a valuable thing). Lots of amateur engineers over the years have tried building their own energy-generating bikes to, say, run their coffeemaker in the morning. Several companies have cropped up in recent years specializing in retrofitted exercise equipment: ReRev.com in St. Petersburg, Florida, for example, which installed a set of retrofitted elliptical machines in a 28,000 member gym in Gainesville, or entrepreneur Jim Whelan's Green Revolution. There's an entire research program devoted to human-powered energy at the Delft University of Technology in The Netherlands.

For the Green Microgym, Boesel started with four linked Team Dynamo stationary bikes connected to a bank of batteries, capable of generating up to 200 watts for every hour of exercise -- enough to run an LCD TV and stereo system for the entire workout period. It's a team effort, too, with all four riders helping to charge the batteries.

Sounds good in theory; Boesel found in practice that the battery option isn't nearly as efficient in generating useful energy as a machine with a "grid-tie" inverter that sends the generated energy directly into the power grid. (That's a device that lets people with solar panels, for instance, "spin the meter backward" and sell power back to their local power company. Boesel literally plugs those machines right back into the wall socket.) There is a greater conversion loss when you feed that generated energy back into the battery, for some reason.

See, that's why you need to do the experiment. Nonetheless, Boesel has reduced his energy costs significantly: he consumes on the order of 9 kilowatt hours per month, which is ridiculously low for a commercial enterprise. In addition to retrofitted machines, he employs a lot of common-sense conservation measures, like turning off machines and TVs when they aren't in use, and judicious use of the A/C and lighting. Apparently the average treadmill takes 1500-2000 watts to operate; you'd need nine Lance Armstrongs chugging at full power to keep just one of those suckers operating. Incremental improvements can add up over time, particularly for a small business like the Green Microgym. He estimates he saves between $75 and $150 a month, which isn't going to set Wall Street on fire -- but it can help defray the creeping costs of running your own gym.

I don't know exactly how much energy my gym in LA uses, but it's a hell of a lot more than the Green Microgym's consumption. Granted, it's a lot bigger, with more machines (each with its own little TV monitor), a cutting-edge sound system, large mounted TVs all over the gym, a heated pool, large locker rooms with sauna and steam room and showers, etc. But there's a lot of little ways to eliminate waste here and there -- like turning off the mounted TV screen on your elliptical machine after you're done working out, or feeding the energy produced by the exerciser back into running the little TV screen. And given the amount of sunshine LA gets in a typical year, I'm constantly surprised by how few places make use of solar panels. Yeah, yeah, they're expensive, and existing buildings can be difficult to adapt to that kind of renewable energy source. But it's a terrific future investment in sunny SoCal.

In general, we routinely overestimate how many calories we burn when we exercise (and underestimate how many food calories we consume). Seeing just how little energy I produce on Boesel's retrofitted elliptical is an eye-opener in itself, particularly since the resistance increases the harder I work. I'm breaking a sweat, starting to breathe hard, and the little light bulb he's hooked up to the front of the machine as part of the test phase barely stays lit. (The retrofitted elliptical was built with help from students at the local university.) I always suspected my gym's machines were overly optimistic about my physical exertions. Boesel has actually worked really hard to make sure his retrofitted machines feel just like the old ones, giving the user control over the resistance level. But once you're talking about watts instead of calories burned, you're dealing with smaller numbers. Some of that is related to body mass: Boesel figures he can produce 75-80 watts consisently -- that is, at a pace he can sustain for a full hour's workout -- compared to my measly 40 watts (and frankly, half the time during my mini-workout the gauge dips into the 30s -- the shame!).

The body is a heat engine, as physicists well know, and thermodynamics is a tricky thing, with many different factors coming into play. It's easy to come up with a wrong or misleading answer -- hence the recurrence of folks convinvecd they've just invented a perpetual motion machine. (Once again, for the record: there is no such thing as "free" energy.) Matt over at Built on Facts had a terrific post about this last December, just in time for Christmas, about the effect climbing a steep hill has on how many calories someone would burn during the climb. "If you're going a long way uphill your height changes quite a bit, and correspondingly, so does your potential energy," he explains.

Being a thorough sort of guy, Matt actually crunched some numbers for how many calories a 160-pound man would burn climbing the stairs of the Empire State Building, based on that increase in potential energy. He assumes you reach the top 1050 feet above ground, and assumes a gravitational acceleration of 9.8 meters per second squared. The answer: he found a total change in potential energy of 230,000 joules. Woo-hoo! At least until you convert that into calories. It's about 54 food calories. Now you're less ecstatic, aren't you? Let Matt explain what's going on here:

Surely something that difficult would burn a lot more calories, you'd think. And it does. The immense effort you expend in climbing is mostly budgeted to different bodily processes. You have to move extra air in and out of your lungs. You have to circulate blood at a much higher rate. You have to process the complicated chemistry required to keep your muscles moving. All of these things take energy and by the time the shoe meets the stair most of the energy has already been lost, eventually ending up mostly in the form of heat. Your body can't afford to overheat and so you begin sweating to carry the excess heat away. All that energy had to come from somewhere and it came from the food you ate. By the time you're on the observation deck looking over Manhattan, you'll have used up a lot more than 54 calories.

In other words, it takes energy to run your body's machine. That's great news, potentially, for your waistline (depending on one's total caloric consumption), but the human body is an energy hog. In that respect, it's a highly efficient little heat engine, because by the time it gets done extracting energy for all those functions, there's precious little available to be harnessed as usable work. We see the same effect in Boesel's Green microgym. The BBC ran an article about this back in 2006, quoting energy consultant Graeme Bathurst, who said bluntly, "The key issue in this case is that human don't use very much energy."

If someone eats 2000 calories a day, that translates into just enough energy to run a 100-watt bulb for 22 hours -- assuming 100% efficient conversion, which doesn't exist. Something is always lost in the conversion -- in the case of exercisers, we lose energy by sweating off excess body heat, for example -- which is why many physicists refer to those pesky laws of thermodynamics as the laws of "thermogoddammics." Or as Bathurst puts it (far less colorfully), "The energy burnt is not converted directly into mechanical movement, and so it is not possible to harness the full energy usage."

How about that rowing machine mostly sitting idle in my gym? Let's say I rowed furiously on that thing for 10 minutes, thereby burning 100 calories. (We are being optimistic; it would be much less, particularly given my pathetic lack of upper body strength these days.) That's enough to run a 100-watt bulb for one hour on paper, but we'd be lucky to harness 50% of that. For a gym with 40 machines of all sorts -- rowing, cycling, running, walking, ellipticals -- that means users could generate some 25kWh of electrical energy during the two-hour peak period of the gym. Again, we're being idealistic, assuming all the machines would be in use and "that all individuals were genuinely attempting to work out," according to Bathurst. (We're looking at you, Princess, the girl in full makeup and swanky color-coordinated gym togs talking on her cellphone while strolling on the treadmill, not breaking a sweat. Get moving! You're ruining our overall energy output!)

That's not going to save the gym much money in terms of overall operating costs, but it's equivalent to running a few households for a day. It's probably sufficient to run your little TV monitor, or recharge your iPhone before heading home. According to an article last year in the Christian Science Monitor, a gym in Boston has a special stationary bike retrofitted to have a laptop built into the top. The laptop has no battery. It is powered entirely by the person pedaling, so someone can get in a decent spinning workout and still surf the Web and answer a few emails.

I am not sure this approach would work for me: I like to push myself and really work up a sweat at the gym, which means I get winded. When I get winded, I can't really focus on things like responding coherently to an email. Plus, the article doesn't say anything about whether sweat dripping onto the keyboard would damage it; anyone who's spilled tea or soda on their keyboard can attest that these are fragile things. But I could definitely be motivated to run a DVD player or small TV monitor or my iPod from my own exertions. Boesel actually sells retrofitting kits for home exercise equipment, and assured me I could probably find a refurbished spinning cycle for half price on E-Bay. (He's right; I checked.) It wouldn't take up much space in the downstairs guest room. I must take this matter up with the Spousal Unit, because even if I don't end up generating much overall energy, it would be kinda fun to do the experiment.

My gym is a long ways off from being able to break even on its energy costs, even if they retrofitted all their equipment tomorrow. Even Boesel's Green Microgym hasn't achieve 100% efficiency yet; the poor economy hasn't helped. But he's getting close! Add in the investment costs for retrofitting equipment, adding solar panels and other energy efficient approaches, and it's easy to see why venture capitalists might not be keen on the idea of green microgyms as a business prospect. It might not be a model that can scale up beyond a community gym, but I'm rooting for Boesel as he tries to take things to the next level.

Personally? I think they're missing the larger perspective. Sure, the current gym "culture" is one of energy waste, and such habits can be hard to break en masse. Nonetheless, it can be done. Regular readers know I drive a Prius since moving to Los Angeles (before that, I was a public transport kind of girl, which is easy to do in NYC and Washington, DC). My favorite feature is the graphical display that shows you exactly how many miles per gallon you're getting at any given moment. And that constant influx of real-time information makes me appreciate all the more just how much energy we consume when we drive our 3000+-pound cars. It has literally altered my driving behavior. I accelerate more slowly, take advantage of downhill sections of the road to coast a bit, brake less suddenly, etc., all for the thrill of the occasional tiny inch upwards in my overall average MPG. (I'm currently at 49.5 MPG over 2-1/2 years of combined city/highway driving, and counting.) This combination of practices is common among Prius drivers, and even has its own term: "hypermiling."

Are we saving the planet? Not really -- not when you consider the energy costs that go into building and transporting our cars in the first place, and other peripheral costs. Ours is a complex, highly interconnected energy environment; that's what makes even basic thermodynamics such a bear to contend with. But I am personally saving money on gas. And the Prius has made a difference, in thousands of tiny, hard-to-quantify ways. Just like driving a Prius has made my hyper-aware of how much gas I burn, so, too, can retrofitting exercise machines help raise people's awareness of just how much hard work it takes simply to light a 60-watt bulb. And that can only be a good thing. Adam Boesel can bring a Green Microgym to Echo Park whenever he wants. I'll be his very first gym member...

There's an obscure science fiction short story by William Morrison (a.k.a., Joseph Samachson), called "A Feast of Demons," in which a scientist creates a hardy little band of so-called "Maxwell's demons," capable of changing the temperature of various objects, and even reversing or accelerating the aging process in humans. (Naturally the demons run amok and weak havoc on an unsuspecting civilization. Otherwise there would be no plot!) The story is included in a collection edited by Ken Kesey, The Demon Box; in fact, all the stories explore similar themes, based on one of the most famous physics thought experiments of the 20th century (second only to the infamous Schroedinger's cat), devised by a Scottish physicist named James Clerk Maxwell.

It all started with that pesky second law of thermodynamics, a.k.a., "thermogoddamnics" to those who fight a losing battle against entropy -- i.e., everyone, whether they realize it or not. That's the one that says, basically, not only can you not have a closed system that puts out more energy than you consume, but you're always going to lose a little bit of energy in the energy conversion process. We're talking about converting potential energy into kinetic energy. One of the neat things about thermodynamics is that if you can create a large enough differential -- for example, a big difference in temperature between, say, two compartments -- you've got yourself a handy energy source to tap into should the need arise.

Refrigerators work on this simple concept, known as the Carnot cycle. Gas (usually ammonia) is pressurized in a chamber, said pressure causes that gas to heat up, this heat is then dissipated by coils on the back of the appliance, and the gas condenses into a liquid. It's still highly pressurized, sufficiently so that the liquid flows through a hole to a second low-pressure chamber. That abrupt change in pressure makes the liquid ammonia boil and vaporize into a gas again, also dropping its temperature -- thereby keeping your perishable foodstuffs nicely chilled. The cold gas gets sucked back into the first chamber, and the entire cycle repeats ad infinitum -- or at least as long as the appliance is plugged in. That's always the catch, you see. The refrigerator is not a truly "closed system": it gets a constant influx of energy from the wall outlet that enables it to operate continuously. Left on its own, without that crucial influx, and the interior would cease to be nicely chilled, and all the food therein would perish.

So that's the second law of thermodynamics, and frankly, it's pretty unyielding. But while it can't be broken, perhaps it can be bent by a cunning infusion of energy that escapes detection by all but the most perceptive eye. James Clerk Maxwell proposed the most famous evasion of thermodynamics back in 1871, dubbed "Maxwell's Demon." Maxwell was one of those kids who liked to know how things worked, taking things apart and trying to put them back together again -- one assumes not always successfully, which must have been quite trying for his parents. He ended up earning a degree in mathematics and taking a chair in natural philosophy at King's College in London, where he formed his famed equations for electromagnetism that are still in use today.

But he was equally fascinated by thermodynamics, notably the fact that heat cannot flow from a colder to a hotter body. And one day Maxwell had an idea: what if hot gas molecules merely had a high probability of moving toward regions of lower temperature? He envisioned an imaginary, tiny creature who could wring order out of disorder to produce energy by making heat flow from a cold compartment to a hot one, creating that all-important temperature difference. The imp guards a hypothetical pinhole in a wall separating two compartments of a container filled with gas -- similar to the two chambers in a refrigerator -- and can open and close a shutter that covers the hole whenever it wishes.

Now, the gas molecules in both compartments will be pretty disordered, with roughly the same average speed and temperature (at least at the outset), so there's very little energy available for what physicists call "work": technically, it's defined as the force over a given distance (W=fd), and it means that you'll spend the same amount of energy carrying a heavy load over a short distance, as you will carrying a feather over a very long distance. But I digress. It Maxwell's thought experiment, the atoms start out in a state of thermodynamic equilibrium. But they're still jiggling around all the time, as atoms are wont to do, so over time, there are small fluctuations as some molecules will start moving more slowly or more quickly than others, balance will soon be restored, since the excess heat will be transferred from hotter to colder molecules until they are all once again in equilibrium.

Ah, but then Maxwell's little demon interferes. Whenever it spots a molecule moving a bit faster in the right compartment and start to move towards the pinhole, he opens the shutter just for a moment so it can pass through to the left side. It does the same for slower molecules on the left side, letting them pass to the right compartment. So what happens as time passes? The molecules in the left compartment get progressively hotter, while those on the right side get colder. The creature creates a temperature difference, and once you have that, well, it's a trivial matter to harness that difference for work. Entropy has been outwitted -- or so it would seem. (You can embrace your inner science imp and play a nifty online game of Maxwell's Demon here.)

Maxwell was too clever by half: in reality, his thought expression was a trick question. Maxwell himself supplied two reasons why his clever little demon couldn't exist in the physical world. First, it's statistically impossible to sort and separate billions of individual molecules by speed or temperature; Nature just doesn't do this. You can't throw a glass of water into the sea and expect to get back the exact same glass of water, right down to the last single molecule.

Okay, perhaps hypothetically you might be able to do this, provided you knew the exact speeds and positions of each and every molecule (at the quantum level, of course, this is an impossibility thanks to the Uncertainty Principle). But you'd have to expend a huge amount of energy to collect that detailed information, far more than the energy you'd get out of the system once you'd succeeded in creating the crucial temperature difference. And that's the catch. (There is always a catch. Energy is never "free.") Just like the refrigerator, Maxwell's mischievous little imp also requires energy to operate. There is no such thing as a perfect heat engine; you'll always lose some heat in the process. That's the bane of every researcher striving to develop alternative energy sources, and they have to be cost-competitive as well as energy-efficient.

That hasn't kept physicists from playing around with the concept of Maxwell's Demon experimentally in the ensuing 130+ years, and it's been a busy year in this area so far. First, a January 31, 2008, article in Physics World described a nifty manmade molecular machine created by another Scotsman, David Leigh, and his colleagues at the University of Edinburgh. Most biological processes involve driving chemical systems away from thermal equilibrium, so Leigh devised a chemical "information ratchet" that performs much the same role as Maxwell's hypothetical demon: creating a temperature difference out of thermal equilibrium, thereby seemingly "reversing" entropy. To quote from the article:

"To perform the feat, they use 'rotaxane,' an assembly of molecules comprising a dumbbell-shaped axle on which a ring can slide, hindered only by a gate located part way along. By shining light on rotaxane, the ring absorbs photons and transfers energy to the gate, which then temporarily changes shape to let the ring pass. Once the ring has passed, however, it cannot transmit energy back to the gate, and is therefore stuck -- or ratcheted -- in place."

It still requires an extra influx of energy to operate the chemical "ratchet," according to Leigh, but nonetheless, it's definitely another step towards the practical realization of manmade molecular machines similar to those found in Nature.

Then, in the March 7 Physical Review, a paper appeared by Mark Raizen and Gabriel Price of the University of Texas at Austin, describing their experiments with a laser-based cooling trap combined with a magnetic trap, divided by a barrier beam. The setup is a little complicated-- you can read the details here -- but in essence, one laser beam serves as the "barrier" while another excites certain atoms of specific frequencies. The end result is a "sorting" of atoms, such that eventually all the atoms end up on one side of the barrier.

Raizen and Price first conceived of the device in 2005 as a means of cooling gases to very low temperatures, perhaps even just a few degrees above absolute zero. Laser cooling has been around in some form or another since the mid-1980s, when Stanford physicist Steven Chu first wove a "web" out of infrared laser beams to create what he called "optical molasses." The beams keep bombarding the atoms with a steady stream of photons -- a bit like hail constantly hitting you in the face -- tuned to specific wavelengths so that they will only be absorbed if they collide head-on with an atom. This causes the atoms to slow/cool down.

Laser cooling was combined with evaporative cooling in the 1990s to produce the world's first Bose-Einstein condensate (BEC), an exotic state of matter first predicted by Albert Einstein and the Indian physicist Satyendra Bose in the 1920s. Get atoms cold enough, they reasoned, to a few billionths of a degree above absolute zero, and they will be packed so densely that they'll coordinate themselves like one big "superatom." It took 70 years, but by gum, physicists succeeded. The work earned Carl Wieman, Eric Cornell, and Wolfgang Ketterle the Nobel Prize in Physics in 2001, and the honor was justly deserved. But BECs to date have only been achievable with specific kinds of gases, like rubidium or cesium. That's why Raizen and Prize's method was so intriguing. Not only would this enable physicists to study even more exotic states of matter, it might also give us new types of atomic clocks (which currently use cesium atoms, mostly, for keeping time).

And now a paper has just appeared in the June 20 Physical Review Letters describing another innovation on the laser-based Maxwellian demon concept, this one devised by Daniel Steck of the University of Oregon in Eugene. It's another laser barrier set-up in which the beam lets atoms pass through only in one direction, such that they all eventually end up on a single side, chilled to extremely low temperatures. Steck created a "box" out of laser light/electromagnetic fields, and then added two parallel lasers that together serve as the "trapdoor." The beam on the right is the barrier, and the one of the left is the "demon," responsible for the "sorting." In concept, it's similar to Raizen and Price's method and the secret, according to Science News' Davide Castelvecchi, is a subtle one:

"Like all lasers, Steck's pumping beam is an orderly arrangement of photons, all traveling in the same direction. And a photon increases the energy level of a rubidium atom by scattering off of it. 'But the scattered photon goes in a random direction,' Steck observes. So while the atoms get a little more order in their lives, the pumping laser ends up with a little less."

In other words: it's a tradeoff. I told you energy is never free. Note, also, that all of these experiments emphasize that they cool the atoms to fractions of a degree above absolute zero (technically defined as minus 495 degrees Fahrenheit), without ever actually reaching that fundamental limit. That's the unofficial "third law" of thermodynamics. All atoms vibrate to some degree. How fast they vibrate depends on heat: the hotter they are, the faster they vibrate, the colder they are, the more slowly they vibrate. But they never cease to move entirely and exist in a state of absolute rest, so to the best of our knowledge to date, absolute zero is impossible to achieve.

Physicists devised this handy mantra summing up the basics of thermodynamics: you can't win, you can't break even, and you can't get out of the game. Now that is truly demonic.

"My building has every convenienceIt's gonna make life easy for meIt's gonna be easy to get things done..."

-- "Don't Worry About the Government," Talking Heads

I was in Berkeley, California, this weekend to attend a conference on the physics of sustainable energy sponsored by the American Physical Society (with the added bonus of getting to meet Chris Clarke, who writes one of my favorite blogs: Creek Running North). I drove up from Santa Barbara Friday afternoon in my shiny red Prius. It fits right in here among all the "Greenies." Let the naysayers knock the Prius if they must, but thanks to the onboard computer and real-time graphical display, I'm now hyper-aware of how much energy I consume by driving, and how much even tiny changes in design, behavior or terrain/environmental conditions can result in big savings (or big losses) over the long haul.

For instance: Accelerate gradually, and you'll use slightly less energy than if you put pedal to the metal in a vain attempt to go from 0 to 60 in a few seconds. In general, the faster you go, the more energy it takes to maintain that speed, so driving just at (or slightly under) the speed limit can also result in energy savings. Driving uphill uses more energy than coasting downhill (any avid bicyclist could tell you that much), and driving into a high wind uses up more gas than driving with the wind at your back. (This is also why it takes less time to fly cross-country going East to West, than it does going West to East.) Don't even get me started on what a 10-hour drive from Salt Lake City to LA in gusting crosswinds through the mountain pass did to my average miles per gallon. (*shakes fist impotently at sky*) Damn you, Nature!

As I wrote when I first bought the Prius last year (after two decades of not owning a car at all), the key to the car's efficiency lies not in one big technological breakthrough -- although that would certainly be nice! -- but in a series of incremental improvements in the overall design of the "system": lighter materials to reduce overall weight (so less energy is required to get the car moving); a braking system that recovers as much wasted heat energy as possible; and using the energy recovered from the brakes and from the motion of the wheels to keep the battery juiced, for example. It's not a perfect design -- there are lots of hidden costs, such as importing some of the raw materials, and those are reflected in the sticker price. There's loads of room for further improvement, but it's a start. For the kind of driving I do in Los Angeles, it's an excellent choice. Plus it provides a handy segue into one of the prevailing themes of this weekend's conference: adopting a systems-based design strategy to eke out every last bit of energy efficiency in our buildings (residential and commercial), industrial complexes, cars and so forth.

We don't really think of a building as an energy system; frankly, even physicists don't spend a great deal of time considering the basic physics of buildings. David Hafemeister (CalPoly), one of the conference organizers, has given the issue of heat transfer in his home a great deal of thought, bemoaning the fact that "We no longer teach such practical things in physics." His talk walked us through an increasingly elaborate calculation of his home's heating needs, trying to take into account a dizzying number of variables (square footage, ceiling height, inevitable thermal losses, local climate, double-paned windows, air ducts, furnace efficiency, body heat given off by inhabitants, etc). I learned a fascinating fact: there is a "free temperature" effect, in which it is 3 degrees F warmer inside the house than it is outside. Based on Hafemeister's calculations, this means that no furnace heating is needed to maintain an indoor temp of around 65 degrees F until the outside temp hits 35 degrees F.

[UPDATE: my notes were unclear, and thus so was the above sentence. It should read: "Based on Hafemeister's calculations, this means that no furnace heating is needed to maintain an indoor temp of 68 F until the outside temperature hits 65 F. If the internal heat is doubled (more people and more electronics) and the total insulation is increased by a factor of five in a super-insulated house, then the furnace won't go on until it is 35 F outside."] That's not likely to happen in southern California, but people in Michigan, take note!

All those factors combine to determine a home's total energy usage -- ergo, it's a system. And just like the Prius, small incremental improvements in energy efficiency in a building "system" can add up significantly over time. Just ask Danny Harvey of the University of Toronto, who spent years developing climate change models before turning his attention to building efficiencies. After all, he reasoned, in developed countries, buildings account for as much as one-third of energy-related greenhouse gas emissions. Much progress has been made on maxing the efficiency of individual devices commonly found in structures: pumps, motors, fans, heaters, chillers, lighting, air ducts, major appliances, and so forth.

But Harvey maintains that putting them all together in the most optimal way could result in systems-level savings many times higher than what can be achieved if we simply continue to address just the individual components. Take your standard heat pump technology, designed to transfer warm air to cooler air. There are some fundamental physical limits to how efficiency the heat pump can be; thermodynamics is a harsh mistress. But Harvey found that by cutting the flow rate through ducts or pipes in half, he could reduce the electricity needed by a factor of 6 or 7.

There's always a trade-off, of course, in this case, a slight loss in efficiency -- otherwise, there might be a reduction by a factor of 8. It's still a considerable savings, and worth the tradeoff in efficiency. No wonder he advocates an integrated design process for future urban planning, complete with computational fluid dynamics modeling. The couple who designed and built the Florida Solar Cracker House near Interlachen would agree. The link is to their Website, detailing everything they did to use as little fossil fuels, and be as energy efficient, as possible.

Lighting is another big energy suck in homes, office buildings, and urban areas (street lights, etc), consuming 22% of all the electricity produced in the US. We could realize huge savings by investing the capital needed to install solid state lighting, i.e., light-emitting diodes. That's a technology whose time has come, frankly, thanks to some major breakthroughs in recent years to improve efficiencies and produce white LEDs with the same broad spectrum as conventional incandescent bulbs, making them commercially viable for the first tie. Right now, researchers are getting 152 lumens per watt with efficiencies between 65% and 85%; by 2012, they think they can reach 280 lumens per watt with 90% efficiencies. At those levels, a solid state lighting system would pay for itself within a couple of years; right now, it takes about five years to recoup the capital investment.

The problem is, they're still pretty expensive, in part because they're made using the same clean-room fabrication techniques used for semiconductor wafers. But LEDs are already a $2 billion a year market. Look around you and you'll see them in all kinds of consumer niche applications: flashlights, cell phone displays, street signage, and several cities are using them in street lights and for the red and green portions of traffic lights. The film and TV industry is very interested in white LEDs because they don't generate heat -- the actors don't have to sweat under hot lights. And spectrally, they're very pure, unlike fluorescent light, which we all know makes us look a bit pale and jaundiced. Nor do they emit UV light, making them ideal for museums (UV light can damage paintings).

All the talk about optimization called to mind one of talks presented at the American Association of Physics Teachers meeting a month or two ago. Students at Issaquah High School in Washington state were on hand with their teacher, Thomas Haff, to present their rather ingenious solution to all that wasted hot water that disappears down the drain during our morning showers. Specifically, they designed a prototype holding tank that stores hot waste water until the heat is dissipated throughout the house, there by cutting down on heating costs.

Haff broached the problem to members of the Student Energy Conservation Group, but he first got the idea 10 years ago, when he spent a year living in rural Japan. Barely 50% of the population there had flush toilets in their home; they relied instead on built-in indoor outhouses (I know, it seems like an oxymoron). These were little more than holding tanks equipped with fans to (ahem) vent the methane and any excess heat out of the house. Once a month the truck would drive through the area and pump out the accumulated waste. (Jen-Luc Piquant thinks that is the ultimate suck-y job.) His first few years back in the US, he lived in a home with no heat in the bathroom, and took to leaving the hot water in the tub after his kids took their baths until it reached ambient room temperature -- a nifty way to solve the bathroom heating problem. And he thought it should be possible to literally collect the waste water from hot showers and use it as a heating source. "People tend to forget that heat is energy," he told me.

That's where Haff's students came in. First they had to determine their basic parameters. Just how long does it take hot water to travel from showerhead to drain? Between five and 15 seconds. Within a minute, all the hot water has entered the municipal waste stream. (Many cities, like Seattle, recycle waste water, but to my knowledge, there's no widespread system anywhere to recapture the wasted heat in that water.) Then they had to determine values for how much water is used during the average shower, starting and ending temperatures of the water collected, and so forth. They then devised a mathematical model and tested it experimentally in the lab. The model and the data matched perfectly. Science! It works!

Their apparatus is a fairly simple design, based on Haff's vision of a holding tank. The tank is made of galvanized steel that fits neatly between the walls of a building. Instead of flowing directly out of the house, hot water from the shower drains into the holding tank. A thermometer monitors the temperature, and when it hits a certain level, the system opens a solenoid valve -- just like those used in dishwashers and sprinkler systems -- which allows the heat to dissipate through the house. You can add vents and blowers and such to the basic passive system to speed the rate of dissipation, but you'll lose some of the benefits, because doing so would reduce the overall efficiency of the system (those add-ons require energy to operate). Haff is now looking into scaling up the prototype for real-world use on a much larger, commercial scale.

See what a systems approach can do for you when it comes to optimizing energy efficiencies? Heck, just unplugging all your "vampire appliances" could result in significant savings to your energy bill, and substantially less carbon emitted into the atmosphere as a result. We're all part of the global energy system, after all.

While the Spousal Unit and I were entertaining an out-of-town friend at Takami, (a great new downtown LA rooftop neo-sushi bar) on Friday night, one of our local pals was really getting into the spirit of things at a UCLA Physics Department bash. He allowed himself to be persuaded to walk across a bed of piping hot coals in a demonstration of firewalking. Now that's a committed physics professor! The upshot? As we were downing our second Lotus Blossom martini and savoring the spicy albacore tuna sashimi -- a specialite de la maison -- poor David was being escorted home with badly blistered feet, and spent the rest of the night soaking his very sore soles in cold water. His enterprising students caught the whole thing on video, and thoughtfully posted it on the Internets for your viewing pleasure. (Listen carefully, and you can hear David exclaim at the very end, "This actually hurts...")

I'm sympathetic to his suffering, unlike Jen-Luc Piquant, who revels in the misfortunes of others. (Schadenfreude is her middle name, or it would be, should she ever get it legally changed from the decidedly non-mellifluous "Marie-Evangeliste.") But some obvious questions arose in my mind. First, the UCLA party was supposed to be Tesla-themed, so what the heck does firewalking have to do with that? Tesla played with electricity, not actual fire, although both can burn, and Tesla did like showy demonstrations with a strong possibility of injury. Maybe that was the rationale. Second, and more to the point, shouldn't a guy smart enough to get a PhD in physics know better than to walk across hot coals?

Like many things in life, firewalking is a bit of a misnomer, since people are really walking barefoot over a bed of hot coals instead of actual flames. The earliest known reference to the practice can be found in an Indian story dating to around 1200 BC, but firewalking shows up in cultures all over the world, spanning thousands of years. Not surprisingly, it's often associated with religious rituals (eg, in certain Eastern Orthodox communities in Greece and Bulgaria), or done to demonstrate the mystical powers of, say, Indian fakirs. You'll also find firewalking in Polynesia, among Japanese Taoists and Buddhists, and performed by certain bushmen in the Kalahari desert as part of their healing ceremonies.

In modern-day America, the practice is more crassly commercial. Sometime in the 1970s, an enterprising snake oil salesman motivational author named Tolly Burkan started offering evening firewalking courses to the public, selling it as a kind of New Age way of confronting one's fears and asserting mind over matter, emerging with a stronger sense of empowerment as a result. Or something. Think "Fear to Power" instead of "Will to Power." He's since founded The Firewalking Institute for Research and Education, and describes the practice as "a method of overcoming limiting beliefs, phobias, and fears." But he doesn't claim that anything supernatural or paranormal is necessarily going on, which is smart, because the science behind firewalking has by now been pretty well documented.

David isn't the first scientifically minded sort to engage in firewalking: noted skeptic Mike Shermer has done it, as has Jearl Walker, a former columnist for Scientific American who has performed firewalking and other insane feats in classroom demonstrations, memorably commenting, "There is no classroom demonstration so riveting as one in which the teacher may die." (No doubt David's physics students would agree.) A physics professor in Pittsburgh named David Willey does it all the time, and has arguably done the most in recent years to spread the word about the underlying physics behind safe firewalking.

There's even been the odd scientific study of what's involved, scientifically, in the firewalking phenomenon, beginning with one performed in the mid-1930s by the University of London Council for Psychical Research. That study concluded that the secret of the successful firewalk is as simple as the low thermal conductivity of the burning wood-turned-to-coal, an insulating layer of ash, and the short time of contact between the hot coals and the soles of the feet. Per Willey: "What I believe happens when one walks on fire is that on each step the foot absorbs relatively little heat from the embers that are cooled, because they are poor conductors, that do not have much internal energy to transmit as heat, and further that the layer of cooled charcoal between the foot and the rest of the hot embers insulates them from the coals." (Check out some of the "firewalking" hyperlinks if you want more on the specifics of heat conduction, etc.)

Armed with that kind of background knowledge, it's not surprising David figured he'd try his hand at it. But if firewalking is supposed to be so safe, and un-magical, and rooted in sound science, why did he get blisters all over the soles of his feet? Well, like most scientific experiments, you have to set them up and perform them correctly to replicate successful results; there's not much margin for error. People do get hurt in such stunts; in 2002, about 20 managers with the KFC fast food chain in Australia were treated for firewalking-related burns. (Insert your own lame "fried chickens" joke here.) Guess that whole "mind over matter, confronting your fears, blah, blah, blah" mantra didn't work so well for them.

I wasn't there to witness David's firewalking, so I can only surmise about what might have gone wrong. The most obvious explanation is that David lingered a bit too long in one place while walking over the bed of hot coals. Except I did see the video, and he seemed to be moving across it pretty quickly. (I, personally, would have bolted across. While wearing protective, flame-retardant shoes.) So maybe there was something not quite right with the set-up. It's critical that the coals be allowed to burn down sufficiently so that they are at a relatively comfy 538 degrees Celsius or so (1000 degrees Fahrenheit), preferably with a thin layer of ash over them providing a bit of extra insulation. This process also burns off any excess water content in the coals; any remaining water would increase both the heat capacity and thermal conductivity of the coals. It's equally critical to make sure no bits of metal have found their way into the coals, because metal has very high thermal conductivity.

Perhaps David could have further lessened his risk of injury by dampening his feet beforehand (the so-called "Leidenfrost" effect, in which a thin layer of sweat or water instantly forms an insulating boundary layer of steam when exposed to intense heat). However, per Willey, this probably isn't a major factor. For one thing, it carries an added risk of coals sticking to your feet as you walk -- increasing exposure time and therefore causing the soles to burn more than if you just crossed with dry feet. (Willey prefers firewalking with dry feet, and also places a water-soaked carpet remnant at the end of the walk for immediate cooling.) Maybe it's something as simple as the fact that D. has very thin soles, and/or insufficiently calloused feet.

The upshot is that David put his faith in theory, trusting that it would be borne out by experiment, further bolstered by the knowledge that it had been borne out by experiment in the past (alas, conveniently neglecting to fully consider the numerous occasions when the experiment failed). It's always a sad thing when scientific experiments don't quite work. Consider the following exchange posted on Overheard in New York, which supposedly took place in a physics lab at City College of New York, after a less-than-satisfactory experimental result. A student points to the equipment and asks, "Um, is this broken?" And the professor (identified as being "Russian") sighs defeatedly, "No. Nothing is broken, except my heart."

For David, it's probably less the intangible pain of a broken heart over a failed experiment, and more the physical discomfort associated with "Yowza, these burn blisters hurt!" Nonetheless, I think he learned a lot from the experience, per his email after I told him I was planning a blog post on firewalking in his honor: "You can tell people that it really hurt, and no creams or sprays helped, not even 30% benzocaine. But ice water worked like a charm." His advice for any aspiring firewalkers? "It's a good idea to hoard Vicodin in advance, which I neglected to do." Heed his words, impressionable young people: David has suffered so you don't have to.

He also had a question of his own, namely, "Why does a burn feel hot even hours after the burn? It must have something to do with swelling, but why would that feel like a burn when other causes of swelling do not?" Good question. If pressed, I'd probably fall back on the first stage of wound healing: inflammation. Blood rushes to the wound site carrying new cells and other useful components for rebuilding tissue, then carries away dead cells, bacteria, and the like. Which in turn makes the wound site feel hot. But it's not the most satisfactory explanation, so commenters should feel free to weigh in with their own thoughts about why this is so. It's not like I've thoroughly consulted WebMD (a.k.a., "The Hypochondriac's Bible") on the subject. (I've been avoiding the site ever since it chastised me for being, like, the millionth person to search the terms "chronic headache" and "brain tumor." Quoth the site (in heavy underlined text): "Most headaches are not an indication of brain tumors." Implied message: "So stop asking us and take some Excedrin already!")

While David is waiting for his feet to heal, and contemplating his own folly while wondering where the firewalking experiment went so horribly wrong, we offer this funky YouTube video of a surfing rats experiment for his amusement. They're call The Radical Rodents, and we think they could give Tyson, the famous Skateboarding Bulldog, a run for his money in the YouTube "Most Downloaded" video awards category. If nothing else, they can take David's mind off the blistering pain. (UPDATE: He can also bask in the glory of being quoted in USA Today.) And once he's mobile again, we'll treat him to Lotus Blossom martinis at Takami, where he can regale the wait staff with tales of his derring-do.

We have not been slacking off on blogging, truly we haven't -- we've just been doing it over at the official blog for the 2007 Industrial Physics Forum all week long. I missed writing an official post for Monday's big "blog for the environment" movement, but as it turns out, I've been learning and blogging all week long about global warming/climate change, the global energy crisis, and the latest advances in alternative energy sources and mitigation strategies. I should get bonus credit! It's been intense: 2-1/2 days of non-stop sessions with blogging in between. We're feeling a bit frazzled and exhausted after three 16-hour days. Also a bit depressed, since that whole global energy crisis? It's big-time serious. And we're running out of time. Fast.

Anyway, to give you an idea of what we've been up to, here's the titles and first paragraphs of the seven IPF posts so far (there'll be one or two more on Friday.) Click on the link to read the entire post.

Think Big, Go Small.The semiconductor industry has been dominated by "Moore's Law" for decades. Every time it seems we're about to reach the threshold beyond which chip size and density can't possibly go any further, some new breakthrough prolongs the lifetime of the silicon chip just a little bit longer. Too bad we're not making comparable strides in the energy sector, because without sufficient energy, how will those sturdy little silicon chips be able to run? Kicking off the 2007 Industrial Physics Forum with an overview of the energy landscape, MIT's Mildred Dresselhaus recommended that we "Think big and go small," and called for "a Moore's Law" for energy efficiency. "A few percent in improvement means nothing" in the grand scheme of things," she insisted: "We need an order of magnitude improvement." [Read more!]

Drive Me Crazy.I confess: I own a Prius. It's not that I think my little hybrid car will single-handedly save the planet, because despite the improvements in fuel efficiency, I'm still burning fossil fuels and putting more carbon into the atmosphere. But it's a start, because hybrids are an economic bridge to the electric cars of the future, according to Michael Tamor, an executive technical leader at Ford Research who spoke this afternoon on the re-electrification of the automobile. "A consumer product will always succeed or fail based on customer value," said Tamor. Indeed, the commercial success of the Prius -- and of the emerging fleet of other hybrid vehicles, from Ford and other automakers -- is due in large part to the fact that people believe they are reaping enough benefits (environmentally and in fuel efficiency) to justify the higher price tag. [Read more!]

Waste Not, Want Not."What am I, chopped liver?" That's what the entire field of thermoelectrics (at least as it relates to waste heat recovery) wants to know. In a field of showy alternative energy candidates like biofuels, solar cells, fuel cells, and powerful wind turbines, the challenge of eking out bits of excess energy that would otherwise be wasted as heat to make incremental improvements in energy efficiency seems a bit, well, proletarian. One could almost envision the poor, lonely drudges doomed to try and recover snippets of wasted heat energy for all eternity in Dante's Ninth Circle of Hell, while Lucifer looks on and snickers. In short, it's a thankless task. Small wonder Lon Bell (BSST LLC and NREL) jokingly calls his work in this area "the chopped liver of new technologies." [Read more!]

LED-ing the Way.One of the standout attractions at Chicago's Millennium Park is the Crown Fountain. On either side of a reflecting pool are two 50-foot glass block towers. Underneath those glass bricks are LED video screens that, when illuminated, showcase videos of the faces of nearly 1000 Chicago residents, in random rotation, all smiling out at the world while a stream of water cascades over their visages. ... The most central technology that makes the Crown Fountain possible is the light-emitting diode (LED). During this morning's session on energy efficiency, Shuji Nakamura of the University of California, Santa Barbara, outlined the current status of LED-based solid state lighting, and some of the existing and emerging applications for these ingenious little devices. [Read more!]

UPDATE: Stefan at Backreaction has an excellent post up about Nakamura's recent pioneering work on blue LEDs. Jen-Luc sez check it out!

The POSEIDON Adventure.Casting about for some small thing you can do to be environmentally responsible? You can always disconnect your doorbell. So says David de Jager, an energy and environmental consultant with E-Concern in The Netherlands. He opened his Tuesday morning presentation by pointing out that an electrical doorbell is pretty much hooked up all the time and therefore draws about 5 watts continuously year-round -- more if it's lit up, and when someone presses it. This works out to something like .01% efficiency, according to de Jager. In fact, the power required to connect all the doorbells in Europe is equivalent to the power output of two coal-fired power plants, all for a convenience we barely use. Quoth de Jager: "This is idiotic." Especially for those of us who don't receive many visitors. [Read more!]

Carbon, Carbon, Everywhere.There's been a great deal of uproar this past week over the controversial awarding of the 2007 Nobel Peace Prize jointly to the UN's Intergovernmental Panel on Climate Change (IPCC) and former vice president Al Gore for their work on raising awareness of climate change and global warming. For all the inevitable politicizing of the issue, what the Nobel Prize Committee's decision truly augurs is the recognition by the international community that global warming is real, and we're quickly running out of time to reverse the potentially catastrophic trends. Honestly? It's probably already too late for merely implementing mitigation strategies, according to Rosina Bierbaum of the University of Michigan. [Read more!]

"Busy Old Fool, Unruly Sun..."Based on the above opening lines from one of his most famous sonnets, the 17th century metaphysical poet John Donne wasn't a fan of Le Soleil. Maybe he just wasn't a morning person, but I suspect the scientists who've been working on photovoltaics for decades, struggling to raise conversion efficiency rates a few points at a time in hopes of some day, in the distant future, making it a commercially viable energy source, might share Donne's frustration. After all, the sun has, to date, proven to be fairly intractable when it comes to harnessing its rays to power our energy-hogging homes. [Read more!]

UPDATE: One more post, not energy-related, from the Frontiers in Physics session:

Measure for MeasureHarvard's Gerald Gabrielse -- who kicked off this year's "Frontiers in Physics" session, which traditionally closes the IPF -- has earned his fair share of professional kudos from the physics community for his groundbreaking research at CERN in Switzerland, coming up with nifty new ways of trapping single particles to study them up close and personal. For instance, back in 2002, his team made science news headlines when they published two papers in Physical Review Letters providing the first glimpses inside an antihydrogen atom. More recently, he's used similar methods to make the most precise measurements to date of the electron's "magnetic moment" -- a finding that AIP's Physics News Update dubbed its scientific breakthrough of the year in 2006. [Read more!]

Whew! I'm getting exhausted all over again reading over that. We'll be back to regular posting at Cocktail Party Physics on Monday, and in the meantime -- the links above should give you plenty to read, and fret over. Me, I'm off to unplug my doorbell and turn off all the lights...

A few years ago, in 2004, a Ben and Jerry's ice cream store in New York City celebrated Earth Day with an unveiling of a prototype "thermoacoustic chiller": basically, a freezer that kept the pints of Cherry Garcia and Chunky Monkey nicely chilled on a warm sunny day by using sound waves, instead of vapor compression of harmful chemicals like hydrofluorocarbons (HFCs) -- the mechanism behind the modern refrigerator. The prototype "chiller" was developed by Matt Poese and Steve Garrett, both physicists at Penn State University.

The underlying effect has been known for over 100 years, after glass blowers in the 19th century observed that tones were being generated by hot glass bulbs attached to a cool tube. Anything that combines thermodynamics with acoustics is A-OK in my book. It's essentially the same basic concept as a standard heat engine, which derives energy from differences in temperature (ref. Sadi Carnot and Maxwell's Demon). I like to think of it as being the temperature equivalent of dropping a ball from a given height. The ball gains more potential energy the higher it is raised, which converts into kinetic energy when the ball is dropped. The higher the ball, the more potential energy is stored, and the more kinetic energy you get when you drop it. Applied to the heat engine, this means that the greater the difference in temperature, the more potential energy there is to convert into kinetic energy. Maybe it's not a perfect analogy, but it works for me.

Of course, unless you can harness that energy to do something useful, it's largely wasted effort. The Penn State scientists figured out how to do that. The concept derives from the fact that sound waves travel by compressing and expanding the gas (air) in which they are generated. This mechanical energy can be used to cool and heat stacks metal plates in the path of the sound wave. Some get hotter, some get colder, and the result is that critical temperature difference that gives rise to usable energy. Put a couple of heat exchangers on that sucker, and you've got a nifty little cooling chamber. Time magazine declared it one of "The Most Amazing Innovations of 2004."

Even better: the gas used is helium, much safer than HFCs. We don't see a lot of thermoacoustic refrigerators on the market just yet because their energy efficiency isn't competitive with the conventional technology. But give it time: scientists are ingenious sorts, and they're making improvements all the time. Thermoacoustic refrigeration is already being used to cool biological samples on board the Space Shuttle.

Poese and Garrett aren't alone. There are lots of research groups working on various fundamental and applied approaches to exploiting this unusual effect -- groups like Orest Symko's at the University of Utah. Symko has a long-standing interest in building tiny versions of thermoacoustic refrigerators for cooling electronics. (Considering how hot my MacBook Pro tends to run, such a breakthrough would be very welcome in the industry.) A couple of years ago, he expanded that program to include all kinds of thermodynamics devices that convert heat into sound, and sound into electricity, for a broad range of possible applications. He and five of his graduate students were on hand at the ASA meeting in Salt lake City to present their latest achievements.

Heat is basically wasted energy, but Symko's devices harness heat that would normally be wasted -- like that emitted by the dual core microprocessor in my MacBook Pro -- and convert it into usable electricity. It's the same basic structure as the thermoacoustic chiller: a small cylinder (the "resonator") that fits in the palm of your hand, containing a stack of metal plates, placed between a cold heat exchanger, and a hot heat exchanger. Take a blowtorch to one end, and air begins to move down the tube, creating sound waves, similar to how a flute produces tones. Also inside the tube is a piezoelectric crystal, a "smart material" that responds to an increase in pressure by producing an electric spark. (Those old cigarette lighters in cars -- since replaced by auxiliary plug-ins -- used piezoelectric crystals.) The tube's dimensions determine the frequency of the sound, in the present case, in the audible range; very small ones could produce ultrasound waves.

Voila! Heat turns into sound turns into electricity. It's not a lot of energy, mind you: Symko estimates that only about 10-25% of the heat is converted into sound, and a little more is lost in the conversion of the sound into electricity, although that's a much more efficient conversion: generally, 80-90% of the sound is converted. Still, you won't see these things being used to power Microsoft's corporate headquarters any time soon. But as an alternative to solar cells in small niche applications, Symko's thermoacoustic devices could be ideal.

There's always a net loss any time you convert one type of energy into another -- that's the basis of the second law of thermodynamics, namely, entropy, a.k.a., The Ultimate Killjoy. It might be a losing battle, but that doesn't mean it's not worth fighting. Someone who wasn't, to my knowledge, in Salt lake City, but perhaps should have been, was Australian scientist Luke Zoontjens, who made news in 2005 with his work on using the sound waves produced from heat derived from car exhaust gases to run car air conditioners. Then a PhD student at the University of Adelaide, Zoontjens sought to exploit the same kinds of thermoacoustic devices, urning heat into sound, and sound into cold air, just like Penn State's thermoacoustic chiller.

You wanna talk about inefficiency? The average gas engine in a car only gets a 30% return in usable energy on the gas it burns; 70% is released as wasted energy, mostly heat. It says something about the extent of the energy problem, and our society, that this is considered an acceptable loss. Zoontjens' scheme converts the heat from a car's exhaust pipe into sound waves, which are amplified inside the tube to as much as 180 decibels. That energy can then be harnessed to cool the car's interior. We're looking at a mere 20% efficiency once everything's been converted, but considering it all comes from what would otherwise be wasted energy, technically, it's a tiny net gain.

Most of us never really stop to think about how powerful sound really is. For instance, we take ultrasound imaging for granted, and because it's so safe, many people might not realize that ultrasound at higher frequencies can burn -- which is why it can be used to cauterize bleeding, particularly in vital organs that have hundreds of tiny blood vessels. It "cooks" the proteins in the blood just like the whites of eggs. I wrote about therapeutic uses of ultrasound several years ago for the (sadly) now defunct magazine, The Industrial Physicist. One of my sources, Larry Crum of the University of Washington, pointed out that the late Princess Diana (back in the news yet again, thanks to a new tell-all biography from publishing doyenne Tina Brown) died from uncontrolled bleeding from all those tiny vessels in the vital organs; had handheld therapeutic ultrasound devices been available at the time of her fatal car crash, the princess might have survived.

Sound is also capable of producing extremely high temperatures through the phenomenon of sonoluminescence, possibly even on a par with nuclear fusion. That was the premise of the 1996 film Chain Reaction, in which Keanu Reeves was implausibly cast as a PhD physicist. (Jen-Luc Piquant notes that donning a white coat and glasses really can't overcome the actor's trademark stoned surfer dude demeanor, any more than it could turn a smokin' hot chica like Elisabeth Shue into a mousy wallflower scientist in The Saint.)

Keanu and his co-star, Rachel Weisz, play physicists who have discovered how to exploit sonoluminescence to achieve "bubble fusion," except instead of a Nobel Prize nomination, Keanu gets framed for the murder of his boss. Oh, and his experiment has been rigged up like an atomic bomb, so he's not only got to clear his name, he has to save the world, too. Just a typical week in the life of the average research physicist, Future Spouse assures me. (Jen-Luc concurs. When she's not trying to diffuse a bubble fusion bomb and foil an international conspiracy, she's struggling to stabilize extra dimensions of spacetime. C'est la vie!)

It might sound like a load of Hollywood hooey, but sonoluminescence is a very real phenomenon -- "the emission of short bursts of light from imploding bubbles in a liquid when excited by sound," per Wikipedia. It was first observed in the 1930s by scientists working on sonar. (There's some debate over who and when, but I'll go with the more detailed story, because it makes for livelier copy.) H. Frenzel and H. Schultes -- neither of whom bore any resemblance to Keanu Reeves (or Rachel Weisz) -- were trying to speed up the photographic development process by placing an ultrasound transducer into a tank of developing fluid. Instead, it caused tiny dots to develop on the film. The fluid had bubbles, you see, and those bubbles were emitting tiny flashes of light whenever the ultrasound was turned on. Since film is photosensitive -- designed to react to light -- the dots appeared on the developed film.

This came as quite a surprise to scientists, but there was one creature who rolled its eyes in disdain over how thick-headed these humans could be sometimes: the lowly pistol shrimp, a.k.a., the snapping shrimp. This species of shrimp has a set of asymmetrical claws, and the larger one produces a loud snapping sound -- loud enough that the pistol shrimp vies with the sperm whale and beluga whale for the title of "loudest animal in the sea." That snapping sound gives rise in turn to a shock wave powerful enough to stun or kill the shrimp's prey (small fish). Such a shock wave also creates bubbles that collapse and produce a flash of light. Granted, it's of a very low intensity, and usually not visible to the naked eye, but still -- the pistol shrimp species would like us to tell you that "shrimpoluminescence" really should have been noticed much sooner than October 2001. If anyone deserves a Nobel Prize for the discovery of sonoluminescence, it's the shrimp.

Frenzel and Schultes discovered what is now known as multi-bubble sonoluminescence (MBSL). They weren't able to do much detailed analysis, because there were far too many bubbles, and those bubbles weren't around long enough (only a few hundred picoseconds) to make detailed measurements or observations. It took over 50 years before scientists were able to produce single bubble sonoluminescence (SBSL) -- coincidentally, that honor belongs to the aforementioned Dr. Crum, and his collaborator, Felipe Gaitan.

Perhaps the shrimp have a valid point about us lagging way behind on the initial discovery, but scientists have made some impressive advances on the sonoluminescent front since Crum and Gaitan's pioneering work on SBSL in 1989. They can make a single bubble expand and collapse over and over again periodically, emitting that telltale flash of light each time it collapses.

With SBSL, it was easier to analyze this complicated process by focusing on a single bubble, which is how scientists learned that the temperature inside the bubble was hot enough to melt steel. Theorists predicted that it could get even hotter, perhaps above 1 million Kelvins. This was exciting because it meant that it might be possible to use sonoluminescence to achieve thermonuclear fusion. (Take that, pistol shrimp, thinkin' you're all that and a bag of chips, just because you have big, loud snappy claws!)

And this is where the controversial topic of bubble fusion -- a.k.a. sonofusion -- comes in. It's possible in principle, per the work of UCLA's Seth Putterman, although he has yet to successfully demonstrate sonofusion in the lab. Someone who claims to have done so is Rusi Taleyarkhan of Oak Ridge National Lab -- a claim that has sparked a heated debate and even raised allegations of scientific misconduct. The so-called "string wars" might dominate the mainstream media coverage, but there's been just as much finger-pointing, name-calling, and snarky put-downs in sonofusion -- and I'd argue it's an equally sexy topic. (Nota bene: this is not -- repeat, not -- cold fusion, even though the apparatus operates at room temperature. The nuclear reactions -- assuming that's what they are -- occur at the very high temperatures inside the core of the imploding bubbles, which shock wave simulations indicate could be as high as 10 megakelvins,)

The chronological chain of events is a bit confusing, given the amount of back and forth that's gone on, and the fact that all the Wikipedia entries on the subject are marked as being "disputed." So I hope people will feel free to post corrections and clarifications in the comments section. But from what I've been able to gather, Taleyarkhan et al. published a paper in Science in 2002 claiming that the results from their experiments on acoustic cavitation were consistent with fusion (most notably, the amount of neutrons released, and tritium produced from the "reactions").

The trouble began when ORNL colleagues repeated the experiments and announced that their neutron and tritium production was more in line with random coincidence. Taleyarkhan's team published a rebuttal, and followed up with published papers with new claims of bubble fusion in 2004 and in 2005, the latter appearing in the peer-reviewed journal Physical Review Letters. But the number of skeptics grew. Among the most vocal was UCLA's Brian Naranjo, who openly questioned the validity of the Purdue results in a 2006 article in Nature.

Part of the problem is that even Taleyarkhan admits that the reaction doesn't always work correctly, and they are still investigating what the critical experimental parameters might be for achieving sonofusion. His claims were extraordinary, and therefore elicited more scientific doubt than usual. Things got really nasty when allegations of misconduct emerged -- namely, that Taleyarkhan had attempted to actively thwart the efforts of several university colleagues to test his claims -- and a special review committee at Purdue was appointed to investigate the matter.

The story ends fairly positively for Taleyarkhan and his collaborators. Earlier this year, Purdue rejected the allegations of research misconduct, stating that "the evidence does not support the allegations" and concluding that "vigorous, open debate of the scientific merits of this new technology is the most appropriate focus going forward." In other words, fight it out in the pages of peer-reviewed journals, people, and leave university administrators out of it.

So the jury is still out on whether these sonofusion research results are valid, i.e., reproducible. Putterman, for one, has not been able to duplicate Taleyarkhan's experiments. Apparently, the BBC documentary series Horizons commissioned Putterman's reproduced experiment -- how cool is that? I dream of a day when CNN, for instance, sponsors such an experiment to resolve a scientific dispute. Ultimately it all comes back down to energy sources, and given global warming, the price of gasoline, and the myriad of other problems associated with how we power our daily lives, it definitely qualifies as being of broad public interest. At least it should.

In the 1992 film, Singles, Campbell Scott plays Steve Dunne, an earnest, idealistic transportation engineer keen on solving Seattle's traffic woes by building a "Supertrain": not just your average commuter system, but one with great music, great coffee and so much luxurious comfort that suburbanites will -- the theory goes -- forego their gas-guzzling vehicles and happily park 'n ride. Steve finally snags a critical five-minute meeting with the mayor, who shatters all his dreams in a single sentence: "People love their cars."

The fictional mayor was right on the money. It's been 15 years since that movie was made, and America is still Car Country, except for a few weird pockets here and there that violate this most fundamental law of US culture -- places like New York City. I never had a car when I lived there. I even managed to live in Washington, DC, for six years without buying a car, thanks to a decent Metro and bus system, and Zipcar -- a stellar example of community-shared vehicles. Los Angeles is different. Sure, there's a sort of subway, still in its infancy, and it might take me to Pasadena in a pinch. But nobody takes the subway to, say, Rodeo Drive. (Jen-Luc Piquant -- an inveterate clothes horse -- is chomping at the bit to get some serious shopping in, and would die of embarrassment if she arrived in anything less chic than a Beamer. An avatar must have standards.) For most of us, a car means freedom: you can hop in and drive anywhere you want, time and funds (and traffic!) permitting.

There are other, less practical reasons why a car is de rigeur in LA. When Future Spouse was apartment hunting last fall and trying to decide on a neighborhood, a local pal told him, "Dude, forget about where you're going to live. What are you going to drive?" One's choice of a car is a statement, you see, a vehicular extension of oneself. So it's very important to pick just the right mode of transport that captures the essence of your soul. Choose -- but choose wisely; by your choice shall you be judged. And I did my best, within my limited means. Yesterday I became the proud owner of a shiny new Prius Touring, in Barcelona red metallic with gray leather interior, and all the bells and whistles. (I chose red because everyone around here seems to drive silver cars, and I want to be able to find mine easily in a crowded parking lot.)

Admittedly, one of the many reasons for choosing the Prius is to assuage my white liberal guilt about abandoning public transportation after all these years. ("It's not you, it's me....") But as personal statements go, I think it suits me: practical, yet kinda stylin', brightly colored, with nifty gadgetry, and most importantly, it says, "I care about the environment." Or more honestly, "If I'm paying over $3 a gallon for gas, I'm damn sure gonna squeeze the utmost energy out of every last drop!" That's an image I can live with.

Cars have changed a lot since the last time I owned one, as auto manufacturers keep coming up with new twists to keep this century-old technology fresh. For starters, almost everything on this puppy is governed by microelectronics and complicated computer algorithms. I'm still figuring out the Smart Key System. Somewhat creepily, the car's computer knows when I'm approaching because it communicates wirelessly with the Smart Key whenever the two come within range of each other. Spoooky. And so much for the element of surprise. (Fortunately, there's also a manual key tucked into the casing for emergencies.) Did I mention the built-in Bluetooth enabled iPod hookup and hands-free cell phone features? How cool is that? And there's so many snazzy special features on the dashboard monitor -- in addition to the cutting edge, voice-activated GPS navigation system -- that I'm surprised there aren't more accidents involving Prius drivers who are too distracted by monitoring their real-time gas mileage to pay much attention to actual traffic.

The point is, there's a helluva lot of science and technology behind a modern car, even if it isn't a fancy hybrid model. Some of it's basic chemistry, like that telltale "new car smell." I've been greedily inhaling the scent whenever I sit in my Prius, mostly because it's such a novelty. But perhaps I ought to be a bit more careful. The odor derives from a complex mixture of volatile organic compounds, "primarily alkanes and substituted benzenes along with a few aldehydes and ketones," according to this handy explanation, courtesy of Chemical and Engineering News'' online resource, "What's That Stuff?"

That's because of all the adhesives and sealants used to hold together the various interior components, whether plastic or fabric. Basically, you've got a bit of residual solvent gas and a few other chemicals wafting about the interior -- those leather seats had to be treated with something, after all. The VOCs aren't present in anything remotely approaching harmful concentrations, but the site does warn about potential ill effects building up over time, and recommends that owners of new cars "make sure there is plenty of outside air entering the vehicle while they drive for at least six months after the vehicle has been purchased." It's been 75 degrees and sunny ever since I got here, so ventilation really shouldn't be a problem. But if I notice an increase in headaches, drowsiness, nausea, eye, nose and throat irritation, and the vague "respiratory distress" -- well, that would be cause for concern.

When it comes to the Prius, however, the smartest science is behind that incredible gas mileage: 60 miles per gallon in the city, and 50 miles per gallon on the highway. It accomplishes this partly by reducing the overall weight of the vehicle -- although at 2900 pounds, one could hardly call the Prius a lightweight. Most cars manufactured today use advanced composite materials for most of the components: plastics and ceramics, very few metals. So does the Prius, but it's also able to lose a bit of extra poundage because it can operate with a smaller internal combustion engine. The battery can pick up the slack when necessary, and the car's computer automatically switches back and forth between the two (it's an impressively smooth transition, too). Less weight means less energy (i.e., gas, combusted) is needed to overcome the car's inertia to get and keep it moving. Plus, it's got all those pretty aerodynamic curves to reduce drag, particularly at higher speeds -- which also translates into less need for energy.

Those features are nice, but I'm most impressed with how the car finds clever ways to recover energy that wold otherwise be lost and store it in the battery for future use --e.g., during deceleration and when stopped at a light. Think about it. The whole point of braking is to reduce the car's accumulated kinetic energy via friction, which releases the energy into the atmosphere as heat. That's the primary cause of wear and tear on brakes. The Prius actually "captures" the heat (how? I have no idea, but they call it "regenerative braking") and recycles it to keep the battery charged. Which is one reason a Prius gets so much better gas mileage in city driving than on highways, unlike a standard gasoline-powered car.

It's an ingenious solution, and will certainly make me feel better about the inevitable traffic jams I'll be experiencing. While other drivers sit there and fume at the wasting of valuable time, I can smugly reflect on the fact that some good is coming out of the delay: my battery is getting some extra juice! Potential energy is being stored, which can then be turned into kinetic energy and harnessed to perform the actual work of overcoming the car's inertia to accelerate forward.

(Jen-Luc wishes to chime in here with a reminder that just because the Prius recycles heat and other forms of energy for further use -- and has an onboard generator that maintains the proper level of charge automatically -- doesn't make it a perpetual motion machine, since it doesn't do so with 100% efficiency. Some of that energy is still lost in translation, thanks to entropy. Otherwise I'd be getting a gazillion miles to the gallon and my battery would last forever. Stupid entropy ruins everything. Thus endeth our little impromptu detour into Newtonian mechanics and classical thermodynamics.)

All this combined has made the Toyota Prius the top-selling hybrid vehicle in the US since it debuted in 2000. Between 2003 and 2004 alone, sales rose 82%, and Toyota had to boost production by 50% to meet the huge demand. Dealerships struggled to keep cars in stock, and it wasn't unusual for there to be waiting lists, sometimes as long as six months. Admittedly, sales have slumped a bit over the last year, but c'mon -- no product, no matter how stellar in concept and execution, can maintain that kind of growth rate indefinitely.

So okay, I'm not quite at the cutting edge of trendiness, but owning a Prius still has some cache. Charlie Eppes, the fictional mathematician on Numb3rs, was shown driving a Prius in an episode earlier this year. And Larry David's fictional counterpart in Curb Your Enthusiasm drives a Prius, which he affectionately calls "Peppy." There's a classic scene where he goes ballistic when he honks and waves at a fellow Prius driver, and said driver doesn't wave back in self-righteous solidarity.

In reality, Larry David is a staunch
environmentalist, and does indeed drive a Prius. So does Angelina
Jolie, Cameron Diaz, and any number of other green-conscious
celebrities. We feel more fabulous already. Sure, I'll be getting lost all over the greater LA area -- at least until I figure out how to program my spiffy new GPS navigational system. I can console myself with the knowledge that I am a member of an elite, though growing, group of drivers. As Larry David's alter ego explained: "We're Prius drivers. We're a special breed."

Physics Cocktails

Heavy G

The perfect pick-me-up when gravity gets you down.
2 oz Tequila
2 oz Triple sec
2 oz Rose's sweetened lime juice
7-Up or Sprite
Mix tequila, triple sec and lime juice in a shaker and pour into a margarita glass. (Salted rim and ice are optional.) Top off with 7-Up/Sprite and let the weight of the world lift off your shoulders.

Any mad scientist will tell you that flames make drinking more fun. What good is science if no one gets hurt?
1 oz Midori melon liqueur
1-1/2 oz sour mix
1 splash soda water
151 proof rum
Mix melon liqueur, sour mix and soda water with ice in shaker. Shake and strain into martini glass. Top with rum and ignite. Try to take over the world.